Fabrication of noble-metal-free copper-doped TiO2 nanofibers synergized with acetic acid-treated g-C3N4 nanosheets for enhanced photocatalytic hydrogen evolution

•Acetic acid-treated g-C3N4 nanosheets with abundant active sites are synthesized and treated with Cu-TiO2 NFs.•Photocatalytic hydrogen evolution properties of all samples under full-spectrum light are studied.•Highly improved photocatalytic hydrogen evolution activity was obtained for the optimal sample containing 0.3 wt% g-C3N4 coated on Cu-TiO2 NFs.•Hydrogen evolution was enhanced by the combined effect of morphology change, copper doping, and heterojunction formation.